The rocks below the fault are known as the footwall. A layer above the fault is the handing wall. Faults are the fractures that form between rocks to form two layers.
Each layer is known as the fault. Many people ask what are rocks below and above a fault called because most confuse their names. We will discuss the details of faults and their significance in the formation of the earth’s surface.
What Is the Rock Above the Fault?
The rock above the fault is known as the hanging wall.
The rocks of the hanging wall go in the upward direction due to the pressure of the rocks in the footwall.
Hanging walls form due to the stress from the forces that move the rocks in a different direction.
People call it the hanging wall because it appears above the footwall.
How Are Rocks Formed Below and Above a Fault Line?
Below a fault line, the intense pressure and heat cause molten metal and rock origins to solidify into solid rock formations.
Above the fault line, the movement of tectonic plates can push and crush different layers of rock together, resulting in new rock formations.
What Are Rocks Below a Fault Called?
The rocks below a fault are called the footwall.
All rock layers do not move in the same direction because one layer goes above the fault line and the other goes below the fault line.
The rocks going below the fault line show movement in a downward direction.
Some people also call it the headwall.
What Is Below the Fault?
There are rocks below the fault.
Rock layers move in specific directions when a fault forms due to stress.
If the fault layers move vertically, you will see rocks above and below the fault line.
The rocks above the fault line are part of the hanging wall.
Few of them are below the fault line also.
These rocks are part of the footwall.
One can say there is a footwall below the fault.
What Is a Fault in Geology?
A fault in Geology is a zone of fracture or a single large fracture between the rocks.
Rocks fractures make faults when a force in the opposite direction forces the rocks to crack and move in the opposite direction.
When the movement occurs slowly in the rocks, we call it the creep.
The movement can also occur rapidly when the rocks store the force in the form of compression.
The rock releases the compressional energy rapidly to produce earthquakes.
Few faults are only a few millimeters long.
Some can reach lengths of thousands of kilometers.
Rocks do not always move in the vertical direction.
Some of them can move in different directions also.
What Are the Different Types of Fault?
You can classify the faults by size, movement direction, and structure.
The best way to categorize them is by the movement of the rock movement.
Rocks can move in any direction on the other fault wall.
We will give you a classification of faults by the rock movement direction.
1. Normal Fault
These faults form when a layer of rocks moves above the fault.
The other layer can stay in the same position or move towards the lower side.
You can see this fault in most places of the world.
It is most common in the ocean ridges system.
This system consists of volcanos that appear on the bottom of the ocean.
2. Reverse (thrust) Fault
It is also a common type of fault that involves the movement of the rocks of the upper layer on the bottom layer plane.
This layer does not force the rocks to move upward to make the wall.
One layer horizontally moves on the layer below.
You can see these faults near the earth’s layers that face compressional forces.
You can see the example of this fault in Japan.
The bottom layer does not go deep into the earth’s layers because it is a shallow fault.
3. Strike-slip Fault
Faults do not move in the vertical direction always.
Some faults can move in other directions also.
Strike-slip faults are the perfect examples of faults moving in the horizontal direction.
The blocks of the rock move past each other rather than moving in upward and downward directions.
- A left-lateral strike-slip fault – The displacement of the rock will be in the same direction when you see it from different directions. You can select the far rock as the reference point. The far rock always moves towards the left side in the left-lateral strike fault.
- A right-lateral strike-slip fault – You can use the same far rock as the reference point in the right-lateral strike-slip type. The far rock will move in the right direction always. It does not matter where you stand because you set a reference point.
What Is the Half of the Fault that Lies Above Called?
The half of the fault that lies above is known as the hanging wall.
When this type of fault forms, a layer goes above, and a layer goes below the fault line.
The half that goes below is known as the footwall.
This phenomenon is present in the normal faults.
You will not see it in the strike-slip type of faults.
The portion that you see above the ground level is the hanging wall.
What Is the Geological Term for Folded Rocks with a Bend at the Bottom?
The geological term for folded rocks with a bend at the bottom is the syncline because they form when the rocks on the surface face a horizontal force.
Some people also call it the downward arc or the fold.
It can form due to differences in the surface forces at a minor level.
Some synclines are at a large scale due to the collision of the tectonic plates.
Which Type of Force Is Responsible for Reverse Fault Formation?
Compressional force is responsible for reverse fault formation.
These faults form when the hanging wall comes above the footwall.
Compressional energy pushes the hanging wall above the footwall.
The reverse fault is known as the thrust fault due to the compressional forces.
Sometimes, the faults store the compressional energy instead of moving in a direction.
When the fault cannot hold, it releases the forces with a thrust. It leads to earthquakes.
Which of the Following Events Allows Rocks on Either Side of a Fault?
When the rocks move horizontally on either side of the rock, it is known as the strike-slip fault.
Shear force is responsible for the formation of the rocks on either side of a fault.
The faults have to move by overcoming the frictional forces.
Sometimes, the frictional forces can overcome the shear forces.
It leads to the accumulation of compressional energy.
An earthquake will move the forces back to balance when the sheer forces overcome the frictional forces.